Electric solder box



July 2, 1940. R. J. RAV! ET A1. 2,206,674

ELECTRIC SOLDER Box Filed'may 11, 1939 INVENTORS 'Pe/'fa Paw' MMM/MATTORNEY Patented July 2, 1940 UNITED STATES ELECTRIC SOLDER BOX ReinoJ. Ravi, Detroit, and Gust R. Linja, River Rouge, Mich.

Application May 11, 1939, Serial No. 273,024

7 Claims.

'I'he present invention pertains to an electric solder box, and theprincipal object is to overcome many of the dimculties experienced withgas heated boxes.

Among these difficulties is the fact that considerable heat is wasted ina gas heated box, due to the fact that the flame is not particularlyconfined. As a result, considerable heat does escape into the air,together with fumes which are detrimental to the worker. Also, theoutside of the box becomes very hot, and the danger of ilesh burns issubstantially increased. Because of the loss of heat .as stated above,the solder is slow to melt. Since the usual gas heated box is notinsulated, the solder is also quick to chill.

The present invention overcomes these objections by providing anelectrically heated box with enclosed heating elements. The box is madeof concrete or some other heat-insulated material with a metal liner forcontaining the solder. The heating elements are embedded in theinsulation and are close to the bottom and two or three of the sidewalls of the liner. Preferably, one side of the box is without a heatingelement, and in this side is mounted a thermostatic control switch whichis affected by the average temperature of the box rather than by thetemperature of the heating elements.

This device melts the solder in a very much shorter time than a gasfurnace and holds the heat considerably longer, so that the solder doesnot chill quickly. There are no fumes around the box and no excessiveheat, which is an indication that little heat is lost. The thermostatmay be set to shut off the current when the device has attained theproper temperature for keeping the solder in a molten condition.

The apparatus is entirely self-contained and, for this reason, can bemade portable in small sizes by mounting on a oor truck or an overheadcarriage. An extension cord extends fro-m the thermostat, and it is onlynecessary to plug the cord into the nearest electrical outlet.

The invention is fully disclosed by way of example in the followingdescription and in the accompanying drawing in which:

Figure 1 is a perspective view of the device,

Figure 2 is a section on the line 2--2 of Figure 1,

Figure 3 is a section on the line 3 3 of Figure l, and

Figure 4 is a wiring diagram, illustrating also the relative position ofthe electrical elements.

(Cl. 21S-44) y Figure 5 is a view of one of the heating ele- E ments.

Reference to these views will now be made by use of like characterswhich are employed to designate corresponding parts throughout.

In Figures l, 2 and 3, the device is illustrated as comprising a box Ihaving an open top 2. The body of the box consists of a suitableheatinsulating material, and for this purpose concrete is preferred. Theconcrete is reinforced by an i0 embedded screen 3 in all its sides.Within the box is a liner 4 of a material, such as steel, unaifected bymolten solder and having no detrimental eifect thereon.

In the bottom and at least two of the side walls of the box is embeddedan electric heating element of the character illustrated in Figure 5.Each such element consists 0f a sheet 5 of mica or other insulation witha resistance ribbon 6 wound thereon in the form of a spiral. Eachelement is placed between two insulating sheets 'l and 8, such as mica,as shown in Figures 2 and 3. These units are assembled in juxtapositionto the outer surfaces of the liner 4 before the concrete is poured.

In the side of the box that is not fitted with a heating element, athermostatic control switch 9 is inserted as may be seen in Figures land 2. An electric cord I0 extends from the switch and is adapted to beplugged into an electric outlet in the well known manner. The switch hasa regulating knob I I for setting the operating temperature. The switchis of well known construction, and the details thereof are therefore notshown.

One of the terminals of the switch is connected by a branched conductorI2 to one end of each winding 6. Similarly, the other terminal of theswitch is connected by a branched conductor I3 to the remaining endsI ofthe windings. Each winding is thus connected across the line andreceives the full line voltage.

In the operation of the device, the solid solder is placed in the box.and the current turned on, either by plugging in or by a switch in theconductor I0. The knob I I is set the circuit when the solder isthoroughly molten. It has been found by experiment that the solder meltsin a fraction of the time required by a gas furnace and remains moltenfor a considerably longer period than in a the heat has been cut off.There is no excessive heat around the outside of the box, and in factthe outer surfaces of the box are not dangerously hot. This is not onlya safety factor in proso that it opens gas heated device, after catesthat the device is operating efiiciently, because of the enclosure ofthe heating elements in the insulated box I. The liner 4 adjacent to theheating element is, on the other hand, a good conductor of heat andconveys heat from the elements to the solder within` the liner.

As previously stated, due to this means and method of heating, there areno unpleasant fumes over the box to annoy the operator and perhapsaffect his health. The device may be made in any desired size, and itWill be evident that the smaller sizes can easily and practically bemade portable. In this respect the device need only be placed on asuitable carriage, since the operating current is obtained merely byplugging the cord l into a convenient electrical outlet.

In the smaller sizes, at least, the element 5, 6 opposite thethermostatic switch may be eliminated. The use thereof in larger sizesis optional, according to requirements.

Although a specific embodiment of the invention has been illustrated anddescribed, it will be understood that various alterations in the detailsof construction may be made without departing from the scope of theinvention, as indicated by the appended claims.

What we claim is:

l. An electric solder box comprising a box having walls of concrete, ametal liner therein, electric heating elements molded in the walls ofsaid box and substantially in contact with the walls of said liner, andan insulating sheet enclosing each element to insulate it from saidliner and to protect it from the concrete.

2. An electric solder box comprising a box having walls of concrete, ametal liner therein, electric heating elements molded in the walls ofsaid box and substantially in contact with the walls of said liner, andan insulating sheet enclosing each element to insulate it from saidliner and to protect it from the concrete, each element beingsubstantially of the same length and breadth of the liner'wall adjacentto which it is disposed.

, 3. An electric solder box comprising a box having walls of concrete, ametal liner therein, electric heating elements molded in the walls ofsaid box and substantially in contact with the walls of said liner, andan insulating sheet enclosing each element to insulate it from saidliner and to said box near the outer surfaces thereon and sublstantially co-extensive with said surfaces.

5. An electric solder box comprising a box having walls of concrete, ametal liner therein, electric heating elements molded in the walls ofsaid box and substantially in contact with the walls of said liner, andan insulating sheet enclos-j ing each element to insulate it from saidliner and to protect it from the concrete, and a thermostatic switchmolded in said box and connected in parallel with said elements, saidelements being connected in parallel to each other.

6. An electric solder box comprising a box having walls of concrete, ametal liner therein, elec-` tric heating elements molded in the Walls ofsaid box and substantially in contact with the Walls of said liner, andan insulating sheet enclosing each element to insulate it from saidliner and to protect it from the concrete, each element consisting of asheet of insulation with lat resistance ribbon wound spirally thereon,said elements being connected in parallel to each other, and athermostatic switch molded in said box and connected to said elements.

7. An electric solder box comprising a box having walls oi concrete, ametal liner therein, electric heating elements molded in the walls ofsaid box and substantially in contact with the walls of said liner, andan insulating sheet enclosing each element to insulate it from saidliner and to protect it from the concrete, each element beingsubstantially of the same length and breadth of the liner wall adjacentto which it is disposed, one of the liner walls having no elementadjacent thereto, and a thermostatic switch molded in said box adjacentto said liner wall.

REINO J. RAVI. GUST R. LINJA.

